So-called twisted pairs having two insulated wires twisted around each other and placed in an insulating jacket are widely used for transmission of relatively low-frequency signals, such as aural signals, in telephone and other communications systems. Such twisted pairs are usually connected by means of patch connectors.
On the other hand, coaxial cables with a 50 Ohm impedance, having an inner signal conductor located inside a dielectric sleeve wrapped in a braided outer grounding conductor covered by an outer insulating jacket, are usually connected by means of standard coaxial connectors of a BNC type. Since in the coaxial cables the central conductor is surrounded by the grounding conductor, the noise level from the outer conductor or to the outer conductor is minimal over the entire length of the cable and its characteristic impedance is uniform, thereby making it suitable for transmission of high-frequency signals or a wide frequency range signals with minimal distortion. Therefore, they are widely used, together with BNC connectors in high-frequency electronic measuring devices.
BNC connectors are connected to coaxial cables with prepared ends. The preparation consists in removal of the insulating jacket from the end of the cable and exposure of the braided outer conductor to a predetermined length. The inner signal conductor, which is usually a solid wire, is exposed by cutting the outer conductor and the dielectric sleeve to a predetermined length. A needle shaped central contact is connected to this inner signal conductor by soldering or crimping. This central contact is inserted in the central cavity of the insulating housing inside the metal shell of the BNC connector. The connection of the outer conductor of the coaxial cable and the metal shell of the BNC connector is usually carried out by crimping a tubular portion of the metal shell directly to the exposed outer conductor of the coaxial cable, or through a conductive ferrule. The tubular portion of the metal shell is usually crimped to a hexagonal or other polyhedral shape. A rotary spring mounted bayonet-type metal fixture is usually attached to the matching, or front, end of the metal shell.
BNC connectors are preferred means for joining coaxial cables, and the connection operation can be accomplished relatively easy by using special tools. But in some cases, it would be desirable to connect a BNC connector to an end of a twisted cable, wherein the other end is attached to a patch connector. However, since BNC connectors are designed primarily for the use with coaxial cables, their use with two-core cables is extremely difficult. Especially difficult is reliably connecting a two-core cable to a metal shell of a BNC connector.
Therefore, the purpose of this invention is to offer an adapter making it possible to easily and reliably connect a two-core cable to a BNC connector.